Secondary battery and battery pack comprising same

Abstract

The present disclosure relates to a secondary battery and a battery pack comprising same. A technical problem to be solved by the present disclosure is to provide a secondary battery and a battery pack comprising same, the secondary battery being capable of ensuring current interruption performance under high current. To this end, the present disclosure provides a secondary battery comprising: an electrode assembly; a case accommodating the electrode assembly and having an opening part and a closing part; a cap plate sealing the opening part; a terminal extending through the closing part and disposed to face the electrode assembly; and a first current collecting member connected to the electrode assembly and the terminal and spaced apart from the terminal when the temperature is at or above a predetermined temperature.

Description

Secondary battery and battery pack including the same

[0001] The present disclosure relates to a secondary battery and a battery pack including the same.

[0002] In general, the demand for high-energy-density, high-capacity rechargeable batteries is rapidly increasing in line with the recent rapid proliferation of battery-powered electronic devices such as mobile phones, laptop computers, and electric vehicles. Accordingly, research and development to improve the performance of lithium-ion batteries is actively underway.

[0003] A lithium secondary battery is a battery comprising a positive electrode and a negative electrode containing an active material capable of lithium ion intercalation and deintercalation, and an electrolyte, which produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated or deintercalated from the positive and negative electrodes.

[0004] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art.

[0005] The purpose of the present invention is to provide a secondary battery capable of securing current blocking performance due to high current and a battery pack including the same.

[0006] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below.

[0007] A secondary battery according to the present invention for solving the above technical problem comprises: an electrode assembly; a case that accommodates the electrode assembly and has an opening and a closing portion; a cap plate that seals the opening portion; a terminal that penetrates the closing portion and is positioned to face the electrode assembly; and a first current collector connected to the electrode assembly and the terminal, and separated from the terminal as the temperature rises above a set temperature.

[0008] The first current collector may include: a first current collector plate having a first plate connected to the electrode assembly and a second plate connected to the first plate and positioned facing the terminal; and a fuse part connecting the second plate and the terminal and melting as the temperature rises above a set temperature.

[0009] The first plate may be arranged to surround the second plate.

[0010] The above terminal includes a terminal surface positioned to face the second plate; and the area of ​​the fuse portion may be equal to the area of ​​the terminal surface or smaller than the area of ​​the terminal surface.

[0011] The first current collector plate is provided to be elastically deformable, and is elastically deformed when the fuse part melts, and can separate the second plate and the terminal.

[0012] The above terminal includes a terminal surface positioned to face the second plate; and the first current collector plate is positioned parallel to the terminal surface and can be bent toward the electrode assembly when the fuse portion melts.

[0013] The above terminal includes a terminal surface positioned to face the second plate; and the first current collector plate is bent toward the terminal surface and can be deformed parallel to the terminal surface when the fuse portion melts.

[0014] The first current collecting member may further include a support member extending from the first current collecting plate toward the closure; and a cavity disposed between the first current collecting plate and the closure.

[0015] The above support member may extend from the first plate.

[0016] The above support member may be positioned to surround the first plate.

[0017] The second plate may include a hinge portion extending from the first plate toward the terminal; and a connecting portion connected to the hinge portion and disposed inside the cavity.

[0018] The above terminal includes a terminal surface positioned to face the second plate; and the connecting portion may be positioned parallel to the terminal surface.

[0019] The first current collector may further include a notch formed concavely on the inner side of the second plate.

[0020] The second plate is spaced apart from the first plate, and the first current collector may further include one or more bridges that movably support the second plate relative to the first plate.

[0021] The above bridge is provided to be elastically deformable, and when the fuse part melts, the second plate can be moved away from the terminal.

[0022] The two ends of the bridge are each connected to the first plate and the second plate, and the first current collector penetrates the first plate and may further include a slit that guides the movement of the bridge.

[0023] The first current collector may further include an elastic member disposed between the first current collector plate and the closure portion, which moves the first current collector plate in a direction away from the terminal when the fuse portion melts.

[0024] The first current collector further includes a through hole penetrating the elastic member; and the second plate and the terminal can be arranged to face each other through the through hole.

[0025] It may further include a second current collector connected to the electrode assembly and the case.

[0026] A battery pack according to the present invention comprises: a housing; and a plurality of secondary batteries disposed inside the housing; wherein the secondary batteries comprise: an electrode assembly; a case that accommodates the electrode assembly and has an opening and a closing portion; a cap plate that seals the opening portion; a terminal that penetrates the closing portion and is disposed facing the electrode assembly; and a first current collector connected to the electrode assembly and the terminal, and separated from the terminal as the temperature rises above a set temperature.

[0027] According to the present invention, in the event of thermal runaway of a secondary battery, the electrical connection between the first current collector and the terminal can be cut off by the elastic force of the first current collector itself, thereby preventing ignition or explosion of the secondary battery.

[0028] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0030] FIG. 1 is a diagram schematically showing the configuration of a battery pack according to a first embodiment of the present invention.

[0031] FIG. 2 is a perspective view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention.

[0032] FIG. 3 is a cross-sectional view schematically showing the configuration of a secondary battery according to the first embodiment of the present invention.

[0033] FIG. 4 is an enlarged view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention.

[0034] FIG. 5 is a perspective view schematically showing the configuration of a first current collection plate according to a first embodiment of the present invention.

[0035] FIGS. 6 and 7 are schematic diagrams illustrating the operation process of a first current collection plate according to a first embodiment of the present invention.

[0036] FIG. 8 is an enlarged view schematically showing the configuration of a first current collector member according to a second embodiment of the present invention.

[0037] FIG. 9 is a perspective view schematically showing the configuration of a first current collector member according to a second embodiment of the present invention.

[0038] FIGS. 10 and 11 are diagrams schematically illustrating the operation process of a first current collector according to a second embodiment of the present invention.

[0039] FIG. 12 is an enlarged view schematically showing the configuration of a first current collector member according to a third embodiment of the present invention.

[0040] FIG. 13 is a perspective view schematically showing the configuration of a first current collector member according to a third embodiment of the present invention.

[0041] FIGS. 14 and 15 are diagrams schematically illustrating the operation process of a first current collector according to a third embodiment of the present invention.

[0042] FIG. 16 is an enlarged view schematically showing the configuration of a first current collector member according to a fourth embodiment of the present invention.

[0043] FIG. 17 is a perspective view schematically showing the configuration of a first current collector member according to a fourth embodiment of the present invention.

[0044] FIG. 18 is an enlarged view schematically showing the configuration of a notch according to the fourth embodiment of the present invention.

[0045] FIGS. 19 and 20 are diagrams schematically illustrating the operation process of a first current collector according to a fourth embodiment of the present invention.

[0046] FIG. 21 is an enlarged view schematically showing the configuration of a first current collector member according to the fifth embodiment of the present invention.

[0047] FIG. 22 is a bottom perspective view schematically showing the configuration of a first current collector member according to the fifth embodiment of the present invention.

[0048] FIG. 23 is a cross-sectional perspective view schematically showing the configuration of a first current collector member according to the fifth embodiment of the present invention.

[0049] FIGS. 24 and 25 are diagrams schematically illustrating the operation process of a first current collector according to a fifth embodiment of the present invention.

[0050] FIG. 26 is an enlarged view schematically showing the configuration of a first current collector member according to the sixth embodiment of the present invention.

[0051] FIG. 27 is a perspective view schematically showing the configuration of a first current collector member according to the sixth embodiment of the present invention.

[0052] FIGS. 28 and 29 are diagrams schematically illustrating the operation process of a first current collector according to a sixth embodiment of the present invention.

[0053] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0054] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0055] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0056] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical.' Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0057] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0058] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0059] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0060] Furthermore, where one component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected or coupled to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "coupled" through another component.

[0061] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions such as “one or more” and “one or more” preceding a list of elements modify the entire list of elements and do not modify individual elements of the list.

[0062] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less, unless specifically stated otherwise.

[0063] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0064] The term "use" may be considered synonymous with the term "utilize." As used herein, "substantially," "about," and similar terms are used as terms of approximation rather than degree, and are intended to account for the inherent variation of measured or calculated values ​​that a person skilled in the art would recognize.

[0065] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0066] Spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used herein for ease of explanation to describe the relationship between one element or feature and another element(s) or feature(s) as illustrated in the drawings. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, an element described as "below" or "below" is understood as "above" or "upper" of another element. Thus, the term "below" may encompass both the up and down directions.

[0067] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0068] FIG. 1 is a diagram schematically showing the configuration of a battery pack according to a first embodiment of the present invention.

[0069] Referring to FIG. 1, the battery pack according to the present embodiment may include a housing (1) and a secondary battery (2).

[0070] The housing (1) forms the general outline of the battery pack and can provide a space in which a secondary battery (2) can be accommodated.

[0071] The housing (1) according to the present embodiment may include a housing body (11) and a cover (12).

[0072] The housing body (11) can be formed to have a box shape with an empty interior and one side open. The cross-sectional shape of the housing body (11) is not limited to the square shape shown in FIG. 1, but can be designed to have various shapes such as polygons, circles, and ellipses.

[0073] The cover (12) is attached to the housing body (11) and can close the internal space of the housing body (11). For example, the cover (12) may be formed to have a shape roughly like a plate and positioned to face the open side of the housing body (11). The cover (12) can be fixed to the housing body (11) by various types of joining methods, such as bolting, welding, or snap-fitting.

[0074] The secondary battery (2) can function as a unit structure that stores and supplies power in a battery pack. The secondary battery (2) can be placed inside the housing body (11).

[0075] Multiple secondary batteries (2) may be provided. Multiple secondary batteries (2) may be arranged inside the housing body (11) to form various patterns, such as a grid or a zigzag pattern. Multiple secondary batteries (2) may be arranged side by side. The number of secondary batteries (2) can be varied in design depending on the size, shape, etc. of the housing body (11).

[0076] Multiple secondary batteries (2) can be electrically interconnected by a busbar, etc. Multiple secondary batteries (2) can be connected in various forms of series and parallel connection structures depending on the power specifications of the battery pack, etc.

[0077] In the following description, the secondary battery (2) is described as a cylindrical lithium-ion secondary battery. However, the present invention is not limited thereto, and the secondary battery (2) may be a lithium polymer battery or a prismatic battery.

[0078] FIG. 2 is a perspective view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention, and FIG. 3 is a cross-sectional view schematically showing the configuration of a secondary battery according to a first embodiment of the present invention.

[0079] Referring to FIGS. 2 and 3, the secondary battery (2) according to the present embodiment includes an electrode assembly (100), a case (200), a cap plate (300), a terminal (400), and a first current collector (500).

[0080] In the following description, the secondary battery is described as a cylindrical battery as a lithium-ion secondary battery. However, the present invention is not limited thereto, and the secondary battery may be a lithium polymer battery or a prismatic battery.

[0081] The electrode assembly (100) can function as a unit structure that performs charging and discharging operations of power in a secondary battery.

[0082] The electrode assembly (100) may include a first electrode plate (110), a second electrode plate (120), and a separator (130) disposed between the first electrode plate (110) and the second electrode plate (120).

[0083] The electrode assembly (100) may have a shape wound around a winding axis (C).

[0084] More specifically, the electrode assembly (100) may have a shape in which the first electrode plate (110), the separator (130), and the second electrode plate (120) are stacked together and wound along a clockwise or counterclockwise direction around a winding axis (C). Accordingly, the electrode assembly (100) may have a shape roughly resembling a jelly roll. The cross-sectional shape of the electrode assembly (100) can be designed to have various shapes, such as an ellipse or a polygon, in addition to a circular shape. Here, the winding axis (C) may refer to a straight line penetrating the center of the electrode assembly (100).

[0085] The first electrode plate (110) can function as the positive electrode of the electrode assembly (100). The first electrode plate (110) may be formed to have the form of a foil containing a metal material such as aluminum or an aluminum alloy. The type, size, and shape of the first electrode plate (110) are not particularly limited as long as it is conductive without causing chemical changes in the secondary battery. The first electrode plate (110) may be wound to have a plurality of winding turns around a winding axis (C).

[0086] A first active material layer may be applied to at least a portion of the first electrode plate (110). The first active material layer may be applied to both sides of the first electrode plate (110), or alternatively, it may be applied to only one side of the first electrode plate (110).

[0087] As the first electrode plate (110) functions as an anode, the first active material layer may include an anode active material.

[0088] The cathode active material may be a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound). More specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, iron, and combinations thereof may be used.

[0089] For example, the positive electrode active material may include at least one of lithium-iron-phosphorus oxide (LiFePO4, LFP), lithium-manganese-iron-phosphorus oxide (LiMnFePO4, LMFP), and lithium-nickel-cobalt-manganese oxide (LiNixCoyMnzO2, NCM). Here, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1을 만족할 수 있다. 양극 활물질은 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM) 중 어느 하나만을 포함할 수 있고, 리튬-철-인 산화물(LiFePO4, LFP), 리튬-망간-철-인 산화물(LiMnFePO4, LMFP), 리튬-니켈-코발트-망간 산화물(LiNixCoyMnzO2, NCM)중 어느 두개 또는 이들을 모두 포함하는 것도 가능하다.

[0090] The first active material layer may further include a positive conductive material.

[0091] The positive electrode conductive material is used to impart conductivity to the first active material layer, and any electronically conductive material that does not cause chemical changes can be used. Examples of positive electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc., metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0092] The first active material layer may further include an anode binder.

[0093] The positive binder serves to adhere the particles constituting the positive active material well to each other and also to adhere the positive active material well to the first electrode plate (110).

[0094] Examples of positive binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0095] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0096] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0097] When using a water-based binder as the anode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0098] The above dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0099] The second electrode plate (120) can function as the negative electrode of the electrode assembly (100). The second electrode plate (120) may be formed to have the shape of a foil containing a metal material such as copper, a copper alloy, nickel, or a nickel alloy. The second electrode plate (120) may be positioned facing the first electrode plate (110) at a predetermined distance apart.

[0100] The second electrode plate (120) is not particularly limited in type, size, shape, etc., as long as it is conductive without causing chemical changes in the secondary battery. The second electrode plate (120) can be wound to have a plurality of winding turns around the winding axis (C).

[0101] A second active material layer may be applied to at least a portion of the second electrode plate (120). The second active material layer may be applied to both sides of the second electrode plate (120), or alternatively, it may be applied to only one side of the second electrode plate (120).

[0102] As the second electrode plate (120) functions as a negative electrode, the second active material layer may include a negative active material.

[0103] The negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0104] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0105] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn may be used.

[0106] As materials capable of doping and undoping lithium, Si-based negative electrode active materials or Sn-based negative electrode active materials may be used. Si-based negative electrode active materials may be silicon, silicon-carbon composites, SiOx (0 < x < 2), Si-Q alloys (wherein Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or combinations thereof. Sn-based negative electrode active materials may be Sn, SnO2, Sn-based alloys, or combinations thereof.

[0107] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0108] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0109] The above Si-based or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material.

[0110] The second active material layer may further include a cathode conductive material and a cathode binder.

[0111] The cathode conductive material is used to impart conductivity to the second active material layer, and any electronically conductive material that does not cause chemical changes can be used. Examples of cathode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc., metal-based materials in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc., or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0112] The negative electrode binder serves to adhere the particles constituting the negative electrode active material well to each other and also to adhere the negative electrode active material well to the second electrode plate (120).

[0113] Examples of cathode binders may include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0114] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0115] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0116] When a water-based binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0117] The above dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0118] A separator (130) may be placed between the first electrode plate (110) and the second electrode plate (120). The separator (130) may perform the function of preventing a short circuit between the first electrode plate (110) and the second electrode plate (120) while allowing the movement of lithium ions between the first electrode plate (110) and the second electrode plate (120).

[0119] As such a separator (130), polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer membrane of two or more layers thereof may be used, and a mixed multilayer membrane such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator may be used.

[0120] The separator (130) may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0121] The porous substrate may be a polymer membrane formed from any one of the following: polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyacetal; polyamide; polyimide; polycarbonate; polyetherketone; polyaryletherketone; polyetherimide; polyamideimide; polybenzimidazole; polyethersulfone; polyphenylene oxide; cyclic olefin copolymer; polyphenylene sulfide; polyethylene naphthalate; glass fiber; Teflon; and polytetrafluoroethylene, or a copolymer or mixture of two or more of these.

[0122] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0123] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include, but is not limited to, inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0124] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0125] A pair of separators (130) may be provided. A pair of separators (130) may be arranged to face each other on both sides of the first electrode plate (110) or the second electrode plate (120). A pair of separators (130) may be wound together with the first electrode plate (110) and the second electrode plate (120) around a winding axis (C).

[0126] The electrode assembly (100) according to the present embodiment may further include a first tab (111) and a second tab (112).

[0127] The first tab (111) can be connected to the first electrode plate (110).

[0128] According to the present embodiment, the first tab (111) may extend from the first electrode plate (110) in a first direction parallel to the winding axis (C). Here, the first direction may be exemplified as a direction parallel to the Z-axis and facing upward with respect to FIG. 3. The first tab (111) may be provided in multiple numbers. The multiple first tabs (111) may be arranged along a circumferential direction centered on the winding axis (C). As the first electrode plate (110) is wound around the winding axis (C), the multiple first tabs (111) may be arranged along a circumferential direction centered on the winding axis (C) and simultaneously arranged along a radial direction centered on the winding axis (C). For example, the multiple first tabs (111) may be arranged to form a spiral shape centered on the winding axis (C).

[0129] The first tab (111) may be formed of the same material as the first electrode plate (110). The first tab (111) may be formed integrally with the first electrode plate (110), or it may be manufactured separately from the first electrode plate (110) and then connected to the first electrode plate (110).

[0130] The second tap (112) can be connected to the second electrode plate (120).

[0131] The second tab (112) may extend from the second electrode plate (120) in the opposite direction of the first direction. That is, the first tab (111) and the second tab (112) may be formed to protrude in opposite directions from each other from both ends of the electrode assembly (100) spaced apart in a direction parallel to the winding axis (C).

[0132] The second tab (112) may be provided in multiple numbers. The multiple second tabs (112) may be arranged along the circumferential direction centered on the winding axis (C). As the second electrode plate (120) is wound around the winding axis (C), the multiple second tabs (112) may be arranged along the circumferential direction centered on the winding axis (C) and simultaneously arranged along the radial direction centered on the winding axis (C). For example, the multiple second tabs (112) may be arranged to form a spiral shape centered on the winding axis (C).

[0133] The second tab (112) may be formed of the same material as the second electrode plate (120). The second tab (112) may be formed integrally with the second electrode plate (120), or it may be manufactured separately from the second electrode plate (120) and then connected to the second electrode plate (120).

[0134] The case (200) forms the general appearance of the secondary battery (2) and can accommodate the electrode assembly (100). The case (200) may be provided to be electrically conductive. For example, the case (200) may include at least one material among steel, stainless steel, aluminum, and aluminum alloy.

[0135] The case (200) may include a can (201), an opening (202), and a closing (203).

[0136] The can (201) may be formed to have a cylindrical shape with a roughly circular cross-section. The diameter of the can (201) may be larger than the diameter of the electrode assembly (100). The length of the can (201) parallel to the winding axis (C) of the electrode assembly (100) may be larger than the length of the electrode assembly (100).

[0137] The electrode assembly (100) can be accommodated inside a can (201). The central axis of the can (201) can be positioned so as to be coaxial with the winding axis (C) of the electrode assembly (100).

[0138] The opening (202) and the closing (203) may be placed at each end of the can (201). The opening (202) and the closing (203) may be placed spaced apart from each other along the first direction.

[0139] The opening (202) according to the present embodiment may be formed to have the shape of a hole penetrating one end of the can (201). Both sides of the opening (202) may be connected to the internal space of the can (201) and the external space of the can (201), respectively. During the manufacturing process of the secondary battery (2), the electrode assembly (100) may be inserted into the interior of the can (201) through the opening (202) together with the electrolyte.

[0140] The closing portion (203) according to the present embodiment may be formed to have the shape of a disc placed at the other end of the can (201) spaced apart along the first direction from the opening portion (202). The outer surface of the closing portion (203) may be formed integrally with the inner surface of the can (201) to seal the other end of the can (201). For example, the can (201) and the closing portion (203) may be formed by a deep drawing process. Alternatively, the closing portion (203) may be manufactured separately from the can (201), and its outer surface may be joined to the inner surface of the can (201). A through hole may be formed in the central portion of the closing portion (203) to provide a path for inserting a terminal (400) described later.

[0141] The first tab (111) of the electrode assembly (100) may be positioned to face the closed portion (203) inside the can (201). The second tab (112) of the electrode assembly (100) may be positioned to face the open portion (202) inside the can (201).

[0142] A case gasket (G3) that electrically insulates the electrode assembly (100) and the closure (203) may be disposed between the electrode assembly (100) and the closure (203). The case gasket (G3) can function as a component that electrically insulates the electrode assembly (100) and the closure (203) by blocking direct contact between the case (200) and the first electrode plate (110).

[0143] The case gasket (G3) according to the present embodiment may be positioned between one side of the electrode assembly (100) having a first tab (111) protruding and the inner side of the closure portion (203) positioned to face the internal space of the can (201). The case gasket (G3) may be fixed to the inner side of the closure portion (203) via an adhesive or the like. The case gasket (G3) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0144] The case (200) according to the present embodiment may further include a beading portion (204).

[0145] The beading portion (204) may refer to a portion of the can (201) that protrudes from the inner surface of the can (201) toward the central axis of the can (201) within the entire area of ​​the can (201). The beading portion (204) may be formed by pressing the outer surface of the can (201) from the side adjacent to the opening (202). The beading portion (204) may come into contact with the other end of the electrode assembly (100) from which the second tab (112) protrudes. Accordingly, the beading portion (204) can prevent the electrode assembly (100) from moving or detaching inside the can (201).

[0146] The cap plate (300) can be configured to seal the opening (202) of the case (200).

[0147] The cap plate (300) according to the present embodiment may be formed to have a roughly circular shape. The cap plate (300) may be placed inside the can (201). The cap plate (300) may be placed inside the can (201) facing the other end of the electrode assembly (100) with the beading portion (204) in between. One side of the cap plate (300) may be placed on the beading portion (204). The other side of the cap plate (300) may be placed facing the external space of the can (201).

[0148] A crimping portion (205) for fixing a cap plate (300) may be formed at one end of the can (201) in which the opening (202) is formed. The crimping portion (205) according to the present embodiment may be bent from one end of the can (201) and positioned to face the other side of the cap plate (300) which is positioned to face the external space of the can (201).

[0149] A cap gasket (G1) that electrically insulates the cap plate (300) and the case (200) may be placed between the cap plate (300) and the crimping portion (205).

[0150] The cap gasket (G1) according to the present embodiment may be positioned to completely wrap around the end of the cap plate (300). The outer surface of the cap gasket (G1) may be pressed and fixed to the inner surface of the beading portion (204) and the crimping portion (205). The cap gasket (G1) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc. Accordingly, the cap gasket (G1) electrically insulates the cap plate (300) and the case (200) and can block moisture, foreign substances, etc. from entering between the cap plate (300) and the case (200).

[0151] The crimping portion (205) is positioned to face the other side of the cap plate (300) with the cap gasket (G1) in between, and can press the cap plate (300) toward the beading portion (204) by contacting the cap gasket (G1). Accordingly, the cap plate (300) can be stably fixed on the side of the opening (202) of the case (200).

[0152] The cap plate (300) can be formed of a metal material to ensure mechanical strength, or alternatively, it can be formed of a synthetic resin material that does not have electrical conductivity.

[0153] The terminal (400) is coupled to the case (200) and can be electrically connected to the electrode assembly (100) by the first current collector (500) described later. The terminal (400) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0154] In this embodiment, the terminal (400) can be electrically connected to the first electrode plate (110) of the electrode assembly (100) by the first current collector (500). Accordingly, the terminal (400) can function as a positive terminal of the secondary battery (2). However, the terminal (400) is not limited thereto, and it is also possible for it to function as a negative terminal by being electrically connected to the second electrode plate (120).

[0155] The terminal (400) according to the present embodiment may penetrate the closed portion (203) of the case (200) along the first direction. More specifically, the terminal (400) may be inserted into the interior of a through hole formed in the center of the closed portion (203). The outer surface of the terminal (400) may be spaced apart from the inner surface of the through hole formed in the center of the closed portion (203) by a predetermined distance. Both ends of the terminal (400) may be placed in the internal space and the external space of the can (201), respectively.

[0156] Both ends of the terminal (400) positioned in the inner and outer spaces of the can (201) are compressed by riveting and can be positioned to face the outer and inner surfaces of the closure (203), respectively. Accordingly, the edge region of the terminal (400) may have a cross-sectional shape approximately U-shaped. Accordingly, the terminal (400) can be stably fixed to the case (200) while penetrating the closure (203).

[0157] A terminal surface (401) facing the electrode assembly (100) along a first direction may be formed on one side of the terminal (400) located in the internal space of the can (201). The terminal surface (401) according to the present embodiment may have a planar shape arranged perpendicular to the first direction.

[0158] A terminal gasket (G2) that electrically insulates the terminal (400) and the case (200) may be placed between the terminal (400) and the case (200).

[0159] The terminal gasket (G2) according to the present embodiment may be arranged to completely surround the inner circumferential surface of the through hole formed in the closure portion (203), and the outer surface of the closure portion (203) facing both ends of the terminal (400). Both sides of the terminal gasket (G2) may be in close contact with the surfaces of the closure portion (203) and the terminal (400). The terminal gasket (G2) may be formed from an insulating material such as rubber, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc.

[0160] The first current collector (500) can be connected to the electrode assembly (100) and the terminal (400). The first current collector (500) can function as a component that provides an electrical connection between the electrode assembly (100) and the terminal (400). In this embodiment, the first current collector (500) can be connected to the first electrode plate (110) of the electrode assembly (100). Accordingly, the first current collector (500) according to this embodiment can be exemplified as an anode current collector.

[0161] The first current collector (500) can be configured to be spaced apart from the terminal (400) when the temperature rises above a set temperature. Accordingly, the first current collector (500) can perform a fuse function to forcibly cut off the electrical connection between the electrode assembly (100) and the terminal (400) when thermal runaway or overcurrent occurs in the secondary battery (2).

[0162] FIG. 4 is an enlarged view schematically showing the configuration of a first current collector member according to a first embodiment of the present invention.

[0163] Referring to FIG. 4, the first current collector (500) according to the present embodiment may include a first current collector plate (510) and a fuse part (520).

[0164] The first current collector plate (510) may be positioned between the electrode assembly (100) and the cap plate (300). For example, the first current collector plate (510) may have the shape of a plate with both sides facing the first tab (111) protruding from one end of the electrode assembly (100) and the cap plate (300), respectively. The first current collector plate (510) may be formed of a conductive material such as copper, aluminum, nickel, etc.

[0165] FIG. 5 is a perspective view schematically showing the configuration of a first current collection plate according to a first embodiment of the present invention.

[0166] Referring to FIGS. 2 to 5, the first current collector plate (510) according to the present embodiment may include a first plate (511) and a second plate (512).

[0167] The first plate (511) forms part of the exterior of the first current collection plate (510) and can be connected to the electrode assembly (100).

[0168] The first plate (511) according to the present embodiment may be exemplified as a portion of the first current collection plate (510) that is positioned to face directly the first tab (111) of the electrode assembly (100) within the entire area of ​​the first current collection plate (510). The lower surface of the first plate (511) (based on FIG. 4) may come into direct contact with the end of the first tab (111). In this case, the end of the first tab (111) may be bent in a direction perpendicular to the winding axis (C) to come into contact with the first plate (511). The first plate (511) may be connected to the first tab (111) by various types of joining methods, such as laser welding.

[0169] The second plate (512) forms the appearance of another part of the first current collection plate (510) and can be connected to the terminal (400).

[0170] The second plate (512) according to the present embodiment may be exemplified as a portion of the first current collection plate (510) that is positioned to face directly the terminal surface (401) of the terminal (400) within the entire area of ​​the first current collection plate (510).

[0171] In this embodiment, the second plate (512) may be a central region of the first current collector plate (510) facing directly to the terminal surface (401), and the first plate (511) may be an edge region of the first current collector plate (510) facing directly to the first tab (111) by being arranged to surround the second plate (512). The first plate (511) and the second plate (512) may be formed to form concentric circles around the winding axis (C). The first plate (511) and the second plate (512) may be formed integrally, or alternatively, they may be manufactured separately and then interconnected by welding or the like.

[0172] The fuse section (520) can connect the second plate (512) and the terminal (400). The fuse section (520) can mechanically support the second plate (512) with respect to the terminal (400) and at the same time provide an electrical connection between the second plate (512) and the terminal (400).

[0173] The fuse portion (520) according to the present embodiment may be positioned between the upper surface of the second plate (512) (based on FIG. 4) and the terminal surface (401). The fuse portion (520) may be exemplified by various types of connecting means capable of interconnecting the second plate (512) and the terminal (400) between the upper surface of the second plate (512) and the terminal surface (401), such as a mixture of the second plate (512) and the terminal (400) that has been melted and hardened by laser welding, etc., or a conductive adhesive. The area of ​​the fuse portion (520) may be equal to the area of ​​the terminal surface (410) or smaller than the area of ​​the terminal surface (410).

[0174] The fuse portion (520) may melt as it is heated above a set temperature. Here, the set temperature is the temperature generated between the second plate (512) and the terminal (400) during thermal runaway of the secondary battery (2), and the design can be varied within a range higher than the temperature generated between the second plate (512) and the terminal (400) during normal operation of the secondary battery (2).

[0175] The first current collector plate (510) according to the present embodiment may be provided to be elastically deformable. When the first current collector plate (510) is connected to the terminal (400) by the fuse portion (520), the first current collector plate (510) can be deformed from its initial state and accumulate elastic force. When the fuse portion (520) melts, the first current collector plate (510) is elastically deformed to its initial state by the accumulated elastic force and can separate the second plate (512) from the terminal (400). Accordingly, the first current collector plate (510) can cut off the electrical connection between the second plate (512) and the terminal (400) by its own elastic restoring force without a separate additional structure during thermal runaway of the secondary battery (2).

[0176] The operation of the first current collection plate according to the present embodiment will be explained below.

[0177] FIGS. 6 and 7 are schematic diagrams illustrating the operation process of a first current collection plate according to a first embodiment of the present invention.

[0178] Referring to FIGS. 2 to 7, in this embodiment, the initial state of the first current collector plate (510) may have a shape in which the second plate (512) protrudes convexly toward the electrode assembly (100), for example, in the opposite direction of the first direction, as shown in FIG. 5.

[0179] In this state, the second plate (512) is pressed along the first direction toward the terminal surface (401) by means of a welding rod, etc., and the first current collector plate (510) is deformed into a shape arranged parallel to the terminal surface (401) and can accumulate elastic restoring force. Subsequently, as a fuse portion (520) is formed between the second plate (512) and the terminal surface (401) by the welding process, the first current collector plate (510) can maintain a state parallel to the terminal surface (401).

[0180] As the temperature of the fuse part (520) rises above the set temperature due to thermal runaway of the secondary battery (2), the fuse part (520) may melt into a liquid state.

[0181] Accordingly, the bonding force between the second plate (512) and the terminal surface (401) is released, and the first current collection plate (510) can be elastically deformed in the opposite direction of the first direction and restored to its initial shape.

[0182] More specifically, the first current collector plate (510) is bent in a convex shape protruding toward the electrode assembly (100) while parallel to the terminal surface (401), and the second plate (512) can be spaced apart from the terminal surface (401).

[0183] Accordingly, the electrical connection between the second plate (512) and the terminal surface (401) can be released.

[0184] In this process, the first tabs (111) connected to the first plate (511) may be crushed or bent by the compressive load caused by the elastic deformation of the first current collector plate (510) and may not interfere with the deformation operation of the first current collector plate (510).

[0185] The secondary battery (2) according to the present embodiment may further include a second current collector (600).

[0186] The second current collector (600) may be disposed between the electrode assembly (100) and the cap plate (300). The second current collector (600) may be electrically connected to the electrode assembly (100) and the case (200). In this embodiment, the second current collector (600) may be connected to the second electrode plate (120) of the electrode assembly (100). Accordingly, the second current collector (600) may be exemplified as a negative current collector. The second current collector (600) may be made of a metal material having electrical conductivity, such as aluminum, nickel, copper, etc.

[0187] The second current collector (600) according to the present embodiment may include a flat portion (610) facing the other end of the electrode assembly (100) on which the second tab (112) protrudes, and an extension portion (620) extending from the flat portion (610).

[0188] One side of the planar portion (610) facing the other end of the electrode assembly (100) (upper surface according to FIG. 3) can be connected to the second tab (112). The end of the second tab (112) is in contact with the planar portion (610) and can be connected to one side of the planar portion (610) by laser welding or the like. In this process, the end of the second tab (112) can be bent in a direction perpendicular to the winding axis (C) and parallel to the planar portion (610).

[0189] The extension portion (620) may extend from the edge of the flat portion (610) toward the cap plate (300). The extension portion (620) may come into contact with the inner surface of the beading portion (204). The extension portion (620) may be rounded or bent along the beading portion (204). The extension portion (620) may be connected to the beading portion (204) by welding or the like. Accordingly, the case (200) and the second electrode plate (120) are electrically connected, and the closure portion (203) may function as a negative terminal.

[0190] The extension portion (620) may be formed in multiple numbers. The multiple extension portions (620) may be spaced apart from each other along the edge of the planar portion (610).

[0191] However, the secondary battery (2) according to the present embodiment is not limited thereto, and it is also possible for the second tab (112) of the electrode assembly (100) to be directly connected to the case (200).

[0192] Hereinafter, a battery pack according to the second embodiment of the present invention will be described.

[0193] The battery pack according to the present embodiment may be configured to differ only in the detailed configuration of the first current collector (500) of the secondary battery (2) from the battery pack according to the first embodiment of the present invention.

[0194] Accordingly, in describing the battery pack according to the present embodiment, only the detailed configuration of the first current collector (500) of the secondary battery (2), which is different from the battery pack according to the first embodiment of the present invention, will be described.

[0195] For the remaining components of the battery pack according to this embodiment, the description of the battery pack according to the first embodiment of the present invention may be applied as is.

[0196] FIG. 8 is an enlarged view schematically showing the configuration of a first current collector according to a second embodiment of the present invention, FIG. 9 is a perspective view schematically showing the configuration of a first current collector according to a second embodiment of the present invention, and FIG. 10 and FIG. 11 are drawings schematically showing the operation process of a first current collector according to a second embodiment of the present invention.

[0197] Referring to FIGS. 8 to 11, the first current collector plate (510) according to the present embodiment may have the shape of a flat plate arranged parallel to the terminal surface (401) in an initial state.

[0198] In this state, the second plate (512) is pressed along the first direction toward the terminal surface (401) by a welding rod or the like, and the first current collector plate (510) is deformed into a convex bending shape toward the terminal surface (401) in the first direction, thereby accumulating elastic restoring force.

[0199] As the first current collector plate (510) is deformed into a shape that is convexly bent toward the terminal surface (401) in the first direction, the second plate (512) comes into contact with the terminal surface (401), and as a fuse portion (520) is formed between the second plate (512) and the terminal surface (401) by a welding process, the first current collector plate (510) can maintain a state in which it is convexly deformed toward the terminal surface (401).

[0200] As the temperature of the fuse part (520) rises above the set temperature due to thermal runaway of the secondary battery (2), the fuse part (520) may melt into a liquid state.

[0201] Accordingly, the bonding force between the second plate (512) and the terminal surface (401) is released, and the first current collection plate (510) can be elastically deformed in the opposite direction of the first direction and restored to its initial shape.

[0202] More specifically, the first current collector plate (510) is deformed so as to be positioned parallel to the terminal surface (401) while being bent convexly with respect to the terminal surface (401), and the second plate (512) can be spaced apart from the terminal surface (401).

[0203] The first current collector (500) according to the present embodiment may further include a support member (530) and a cavity (540).

[0204] The support member (530) extends from the first current collector plate (510) toward the closure member (203) and can support the first current collector plate (510).

[0205] The support member (530) according to the present embodiment may extend from the edge of the first plate (511) toward the closure member (203). The end of the support member (530) may come into contact with a case gasket (G3) disposed on the inner surface of the closure member (203). Accordingly, the support member (530) can secure insulation from the case (200).

[0206] The support member (530) may be positioned to surround the first plate (511). For example, the support member (530) may be extended to form a closed curve along the circumferential direction centered on the winding axis (C). The support member (530) may be positioned at a predetermined angle of inclination with respect to the winding axis (C). The support member (530) may be extended at an angle away from the edge of the first plate (511) and away from the winding axis (C).

[0207] The cavity (540) may be positioned between the first current collector plate (510) and the closure portion (203). The cavity (540) according to the present embodiment may be exemplified as the upper space (based on FIG. 8) of the first plate (511) surrounded by the inner surface of the support portion (530).

[0208] Accordingly, the secondary battery (2) according to the present embodiment can suppress the flow of the edge region of the first plate (511) when the first current collector plate (510) is bent by the support member (530), and can secure a space for deformation of the first current collector plate (510) between the first current collector plate (510) and the closing member (203) by the cavity (540).

[0209] The support member (530) and cavity (540) according to the present embodiment can be similarly applied to the first current collector member (500) according to the first embodiment of the present invention.

[0210] Hereinafter, a battery pack according to the third embodiment of the present invention will be described.

[0211] The battery pack according to the present embodiment may be configured to differ only in the detailed configuration of the first current collector (500) of the secondary battery (2) from the battery pack according to the second embodiment of the present invention.

[0212] Accordingly, in describing the battery pack according to the present embodiment, only the detailed configuration of the first current collector (500) of the secondary battery (2), which is different from the battery pack according to the second embodiment of the present invention, will be described.

[0213] For the remaining components of the battery pack according to the present embodiment, the description of the battery pack according to the second embodiment of the present invention may be applied as is.

[0214] FIG. 12 is an enlarged view schematically showing the configuration of a first current collector according to a third embodiment of the present invention, FIG. 13 is a perspective view schematically showing the configuration of a first current collector according to a third embodiment of the present invention, and FIG. 14 and FIG. 15 are drawings schematically showing the operation process of a first current collector according to a third embodiment of the present invention.

[0215] Referring to FIGS. 12 to 15, the second plate (512) according to the present embodiment may include a hinge portion (512a) and a connecting portion (512b).

[0216] The hinge portion (512a) can protrude from the first plate (511) toward the terminal.

[0217] The hinge portion (512a) according to the present embodiment may protrude into the interior of the cavity (540) from the boundary area between the first plate (511) and the second plate (512). The hinge portion (512a) may be extended to form a closed curve along the circumferential direction centered on the winding axis (C). The hinge portion (512a) may be positioned at an angle with respect to the winding axis (C). For example, the hinge portion (512a) may be formed such that the distance from the winding axis (C) decreases as it approaches the end.

[0218] The connecting part (512b) is connected to the hinge part (512a) and can be placed inside the cavity (540).

[0219] The connecting portion (512b) according to the present embodiment may have the form of a flat plate positioned perpendicular to the winding axis (C). The edge of the connecting portion (512b) may be connected to the end of the hinge portion (512a). One side of the connecting portion (512b) may be positioned to face the terminal surface (401) of the terminal (400) along the first direction. The connecting portion (512b) may be positioned parallel to the terminal surface (401).

[0220] The fuse section (520) is positioned between the connection section (512b) and the terminal surface (401) and can mechanically and electrically connect the connection section (512b) and the terminal surface (401). The area of ​​the fuse section (520) may be equal to the area of ​​the connection section (512b) or smaller than the area of ​​the connection section (512b).

[0221] In this embodiment, when the first current collector plate (510) is deformed in a shape that is convexly bent toward the terminal surface (401) in the first direction for connecting the connecting portion (512b) and the terminal surface (401), the bending force generated between the first plate (511) and the second plate (512) is absorbed by the angle change of the hinge portion (512a), and the connecting portion (512a) can maintain a state parallel to the terminal surface (401).

[0222] Accordingly, the secondary battery (2) according to the present embodiment can further improve the weldability between the terminal (400) and the second plate (512).

[0223] Hereinafter, a battery pack according to the fourth embodiment of the present invention will be described.

[0224] The battery pack according to the present embodiment may be configured to differ only in the detailed configuration of the first current collector (500) of the secondary battery (2) from the battery pack according to the first to third embodiments of the present invention.

[0225] Accordingly, in describing the battery pack according to the present embodiment, only the detailed configuration of the first current collector (500) of the secondary battery (2), which is different from the battery pack according to the first to third embodiments of the present invention, will be described.

[0226] For the remaining components of the battery pack according to the present embodiment, the description of the battery pack according to the first to third embodiments of the present invention may be applied as is.

[0227] FIG. 16 is an enlarged view schematically showing the configuration of a first current collector member according to a fourth embodiment of the present invention, and FIG. 17 is a perspective view schematically showing the configuration of a first current collector member according to a fourth embodiment of the present invention.

[0228] Referring to FIGS. 16 and 17, the first current collector (500) according to the present embodiment may further include a notch (550).

[0229] In the following description, the notch (550) is additionally formed in the first current collector (500) according to the third embodiment of the present invention as an example, but the notch (550) is not limited thereto and may also be applied to the first current collector (500) according to the first embodiment of the present invention or the first current collector (500) according to the second embodiment.

[0230] The notch (550) can induce a rupture operation of the second plate (512) during thermal runaway of the secondary battery (2). Accordingly, in the case where the fuse portion (520) of the secondary battery (2) according to the present embodiment does not melt smoothly or the elastic deformation of the first current collector plate (510) does not occur smoothly during a thermal runaway situation, the second plate (512) can be ruptured by the notch (550) to forcibly cut off the electrical connection between the terminal (400) and the first current collector plate (510).

[0231] FIG. 18 is an enlarged view schematically showing the configuration of a notch according to the fourth embodiment of the present invention.

[0232] Referring to FIGS. 16 to 18, the notch (550) according to the present embodiment may have the shape of a groove formed concavely from the surface of the second plate (512) into the inner side of the second plate (512). The notch (550) may extend along a circumferential direction centered on the winding axis (C). The notch (550) may have the shape of a circle with the winding axis (C) as the central axis. Alternatively, the notch (550) may be provided in multiple numbers, and the multiple notches (550) may be arranged at predetermined intervals along a circumferential direction centered on the winding axis (C).

[0233] The distance from the winding shaft (C) to the notch (550) may be greater than the distance from the winding shaft (C) to the outer surface of the fuse portion (520). That is, the notch (550) may be positioned to completely surround the outer area of ​​the fuse portion (520). Accordingly, the notch (550) can induce a breaking operation of the second plate (512) even when the fuse portion (520) is not melted.

[0234] FIGS. 19 and 20 are diagrams schematically illustrating the operation process of a first current collector according to a fourth embodiment of the present invention.

[0235] Referring to FIGS. 16 to 20, when thermal runaway occurs in the secondary battery (2), if the temperature of the fuse portion (520) does not rise above a set temperature or if the first current collector plate (510) is not restored to its initial form after the melting of the fuse portion (520), the second plate (512) is not separated from the terminal surface (401), so the electrical connection between the second plate (512) and the terminal surface (401) may not be released.

[0236] Subsequently, the temperature of the second plate (512) continues to rise, and the heat generated by the second plate (512) is concentrated in a part of the second plate (512) where the notch (550) is formed, out of the entire area of ​​the second plate (512).

[0237] As the temperature of a portion of the second plate (512) in which the notch (550) is formed rises above a set temperature, the portion of the second plate (512) in which the notch (550) is formed melts. Here, the set temperature at which the melting of the second plate (512) occurs may be different from the set temperature at which the fuse portion (520) melts.

[0238] Accordingly, the electrical connection between the central region of the second plate (512) surrounded by the notch (550) and the edge region of the second plate (512) located outside the notch (550) is cut off, and the electrical connection between the terminal (400) and the first current collection plate (510) can also be cut off.

[0239] Hereinafter, a battery pack according to the fifth embodiment of the present invention will be described.

[0240] The battery pack according to the present embodiment may be configured to differ only in the detailed configuration of the first current collector (500) of the secondary battery (2) from the battery pack according to the first to fourth embodiments of the present invention.

[0241] Accordingly, in describing the battery pack according to the present embodiment, only the detailed configuration of the first current collector (500) of the secondary battery (2), which is different from the battery pack according to the first to fourth embodiments of the present invention, will be described.

[0242] For the remaining components of the battery pack according to the present embodiment, the description of the battery pack according to the first to fourth embodiments of the present invention may be applied as is.

[0243] FIG. 21 is an enlarged view schematically showing the configuration of a first current collector according to a fifth embodiment of the present invention, FIG. 22 is a bottom perspective view schematically showing the configuration of a first current collector according to a fifth embodiment of the present invention, FIG. 23 is a cross-sectional perspective view schematically showing the configuration of a first current collector according to a fifth embodiment of the present invention, and FIG. 24 and FIG. 25 are drawings schematically showing the operation process of a first current collector according to a fifth embodiment of the present invention.

[0244] Referring to FIGS. 21 to 25, the second plate (512) according to the present embodiment may be spaced apart from the first plate (511). For example, the outer surface of the second plate (512) and the inner surface of the first plate (511) may be separated from each other.

[0245] The first current collector (500) according to the present embodiment may further include a bridge (560).

[0246] The bridge (560) can movably support the second plate (512) relative to the first plate (511).

[0247] The bridge (560) according to the present embodiment may have the form of a rod, with both ends connected to the second plate (512) and the first plate (511), respectively.

[0248] The bridge (560) may be provided to be elastically deformable. When the second plate (512) and the terminal (400) are interconnected by the fuse portion (520), the bridge (560) may accumulate elastic force through elastic deformation. For example, the bridge (560) may accumulate elastic force by bending in a direction from the first plate (511) toward the terminal (400).

[0249] The bridge (560) is restored to its initial shape by the elastic force accumulated when the fuse part (520) melts, and can move the second plate (512) away from the terminal (400), that is, in the opposite direction of the first direction. That is, the secondary battery (2) according to the present embodiment can be configured to cut off the electrical connection between the first current collector plate (510) and the terminal (400) by the elastic force of the bridge (560) rather than the elastic force of the first current collector plate (510) when thermal runaway occurs.

[0250] The bridges (560) may be provided in multiple numbers. The multiple bridges (560) may be arranged at predetermined intervals along the circumferential direction centered on the winding axis (C). The multiple bridges (560) may be arranged at equal intervals, or they may be arranged at irregular intervals. The number of bridges (560) is not limited to the number shown in FIG. 22, and the design can be changed to a variety of numbers.

[0251] The first current collector (500) according to the present embodiment may further include a slit (561).

[0252] The slit (561) penetrates the first plate (511) and can guide the movement of the bridge (560).

[0253] The slit (561) according to the present embodiment may have the shape of a hole penetrating the first plate (511) along the first direction. The slit (561) may be positioned facing the second plate (512) and the bridge (560). For example, the central portion of the slit (561) may penetrate the central portion of the first plate (511). The area of ​​the central portion of the slit (561) may be larger than the area of ​​the second plate (512). The outer portion of the slit (561) may extend from the central portion of the slit (561) along a radial direction centered on the winding axis (C). The area of ​​the outer portion of the slit (561) may be larger than the area of ​​the bridge (560). The outer portion of the slit (561) may be provided in multiple numbers. The outer portion of the slit (561) may be formed to correspond to the number of bridges (560).

[0254] When the fuse part (520) melts, the second plate (512) and the bridge (560) located between the first plate (511) and the closure part (203) pass through the first plate (511) through the slit (561) and can be moved between the first plate (511) and the electrode assembly (100).

[0255] Accordingly, the secondary battery (2) according to the present embodiment can expand the range of movement of the second plate (512) when the fuse part (520) melts, thereby more reliably blocking the connection between the second plate (512) and the terminal (400).

[0256] Hereinafter, a battery pack according to the 6th embodiment of the present invention will be described.

[0257] The battery pack according to the present embodiment may be configured to differ only in the detailed configuration of the first current collector (500) of the secondary battery (2) from the battery pack according to the first embodiment of the present invention.

[0258] Accordingly, in describing the battery pack according to the present embodiment, only the detailed configuration of the first current collector (500) of the secondary battery (2), which is different from the battery pack according to the first embodiment of the present invention, will be described.

[0259] For the remaining components of the battery pack according to this embodiment, the description of the battery pack according to the first embodiment of the present invention may be applied as is.

[0260] FIG. 26 is an enlarged view schematically showing the configuration of a first current collector according to the 6th embodiment of the present invention, FIG. 27 is a perspective view schematically showing the configuration of a first current collector according to the 6th embodiment of the present invention, and FIG. 28 and FIG. 29 are drawings schematically showing the operation process of a first current collector according to the 6th embodiment of the present invention.

[0261] Referring to FIGS. 26 and 27, the first current collector (500) according to the present embodiment may further include an elastic member (570).

[0262] In this embodiment, the first current collector plate (510) may have the shape of a flat plate parallel to the terminal surface (401).

[0263] The elastic member (570) may be disposed between the first current collector plate (510) and the closing portion (203). The elastic member (570) may be provided to be elastically deformable. The secondary battery (2) according to the present embodiment may be configured to block the electrical connection between the first current collector plate (510) and the terminal (400) by the elastic force of the elastic member (570) rather than the elastic force of the first current collector plate (510) when thermal runaway occurs.

[0264] The elastic member (570) according to the present embodiment may have the shape of a disc spring capable of elastic deformation along a first direction. One end of the elastic member (570) (lower end in FIG. 26) may be in contact with the boundary area between the first plate (511) and the second plate (512). One end of the elastic member (570) may be connected to the first current collector plate (510) by various types of joining methods such as welding, bolting, or bonding. The other end of the elastic member (570) (upper end in FIG. 26) may be in contact with a case gasket (G3) disposed on the inner surface of the closed part (203).

[0265] A through hole (571) penetrating the elastic member (570) in a first direction may be formed in the central part of the elastic member (570). The second plate (512) and the terminal (400) may be positioned facing each other through the through hole (571). The lower part of the terminal (400) protruding into the internal space of the case (200) may be positioned inside the through hole (571). Accordingly, the second plate (512) and the terminal surface (401) may come into contact with each other through the through hole (571).

[0266] When the second plate (512) comes into contact with the terminal surface (401), the elastic member (570) can be compressed in the first direction to accumulate elastic force. Subsequently, when the fuse part (520) melts, the elastic member (570) is restored to its initial shape by the accumulated elastic force and can move the second plate (512) away from the terminal (400), that is, in the opposite direction of the first direction.

[0267] The shape of the elastic member (570) is not limited to the shape described above, and can be designed in various types such as a coil spring, which is installed between the first current collector plate (510) and the closing part (203) and can apply pressure in the opposite direction of the first direction of the first current collector plate (510).

[0268] Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0269] Therefore, the technical scope of protection of the present invention should be determined by the patent claims.

Claims

1. Electrode assembly; A case accommodating the above electrode assembly and having an opening and a closing; A cap plate that seals the above-mentioned opening; A terminal penetrating the above-mentioned closure and positioned facing the electrode assembly; and A secondary battery characterized by including: a first current collector connected to the electrode assembly and the terminal, and separated from the terminal as the temperature rises above a set temperature.

2. In Paragraph 1, The above-mentioned first current collector is, A first current collector plate having a first plate connected to the electrode assembly and a second plate connected to the first plate and positioned to face the terminal; and A secondary battery characterized by including a fuse portion that connects the second plate and the terminal and melts as the temperature rises above a set temperature.

3. In Paragraph 2, A secondary battery characterized in that the first plate is positioned to surround the second plate.

4. In Paragraph 2, The above terminal includes a terminal surface positioned to face the second plate; and A secondary battery characterized in that the area of ​​the fuse portion is equal to or smaller than the area of ​​the terminal surface.

5. In Paragraph 2, The above-mentioned first current collector plate is provided to be elastically deformable, and A secondary battery characterized in that the first current collector plate elastically deforms upon melting of the fuse portion and separates the second plate from the terminal.

6. In Paragraph 5, The above terminal includes a terminal surface positioned to face the second plate; and A secondary battery characterized in that the first current collector plate is arranged parallel to the terminal surface and bends toward the electrode assembly when the fuse portion melts.

7. In Paragraph 5, The above terminal includes a terminal surface positioned to face the second plate; and A secondary battery characterized in that the first current collector plate is bent toward the terminal surface and deforms parallel to the terminal surface when the fuse portion melts.

8. In Paragraph 5, The first current collecting member comprises a support portion extending from the first current collecting plate toward the closure portion; and A secondary battery further comprising a cavity disposed between the first current collection plate and the closure portion.

9. In Paragraph 8, A secondary battery characterized by the above-mentioned support member extending from the above-mentioned first plate.

10. In Paragraph 9, A secondary battery characterized in that the above-mentioned support member is arranged to surround the first plate.

11. In Paragraph 8, The above second plate is, A hinge portion extending from the first plate toward the terminal; and A secondary battery characterized by including a connecting part connected to the hinge part and disposed inside the cavity.

12. In Paragraph 11, The above terminal includes a terminal surface positioned to face the second plate; and A secondary battery characterized in that the above-mentioned connection portion is arranged parallel to the terminal surface.

13. In Paragraph 2, A secondary battery characterized by further including a notch formed concavely inwardly on the second plate in the first current collector member.

14. In Paragraph 2, The second plate is spaced apart from the first plate, and A secondary battery characterized by further including one or more bridges that movably support the second plate with respect to the first plate in the first current collector member.

15. In Paragraph 14, A secondary battery characterized in that the above-mentioned bridge is elastically deformable and, upon melting of the above-mentioned fuse portion, the second plate is moved in a direction away from the terminal.

16. In Paragraph 14, Both ends of the above bridge are each connected to the first plate and the second plate, and A secondary battery characterized by further including a slit that penetrates the first plate and guides the movement of the bridge in the first current collection member.

17. In Paragraph 2, The above-mentioned first current collector is, A secondary battery further comprising: an elastic member disposed between the first current collector plate and the closure portion, which moves the first current collector plate in a direction away from the terminal when the fuse portion melts.

18. In Paragraph 17, The first current collector further includes a through hole penetrating the elastic member; and A secondary battery characterized in that the second plate and the terminal are positioned to face each other through the through hole.

19. In Paragraph 1, A secondary battery characterized by further including the electrode assembly and a second current collector connected to the case.

20. Housing; and A plurality of secondary batteries disposed inside the above housing; including The above secondary battery is, Electrode assembly; A case accommodating the above electrode assembly and having an opening and a closing; A cap plate that seals the above-mentioned opening; A terminal penetrating the above-mentioned closure and positioned facing the electrode assembly; and A battery pack characterized by including: a first current collector connected to the electrode assembly and the terminal, and separated from the terminal as the temperature rises above a set temperature.

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